I've never owned a manual before so this may be a dumb question...

Every once in a while I'll be driving my car and I'll stop for a stop light, so brake and put the clutch in. As the RPMs drop the tach will go below 1k and the car will shake like it going to stall for a second and then it will be fine. Is this normal?

Thanks

 

No, it shouldn't do this. Check your spark plugs, are they tight?

 

I have the same problem, plugs are good and tight. I think it's an "artifact" of the emissions or engine control software. Not sure why- I've had other Hondas do this but not quite as bad.

How bad is it? Mine doesn't go below probably 4 or 500 RPMs, but it does drop, shudder, then come back. Hasn't died, knowing Honda, it never will.

 

My car does this too. It isn't a big deal to me and I also attribute it to the emissions control system. The RPMs will drop to 6-700 for a second or less, associated with a mild shake, and then the engine smooths out. Does it seem to happen more often when warming up? It does in my car.

 

Try doing this:

http://www.s2000online.com/forums/showthre...hlight=shingles

It doesn't look pretty but it seems to have cured the stumbling, bog and rough idling. The Swiss technician who diagnosed my car said that the problem lies with the IAT sensor (software related) of the car. The Intake Air Temperature sensor gives a signal that goes out of range. This out of range reading causes the ECU to retard timing, thus, the bogging, stumbling or rough idling.

This occurs, at least in my case, when outdoor temperature is very high. A fair number of S2 owners have suffered from this problem. The thermal wrap that you see in the link above covers the radiator as to prevent it from pre-heating the air entering the air intake box.

 

Great info (and link)...the temp actuallly causes conflicts between the short term fuel trim (STFT) and long term fuel trim (LTFT) in the ECU, resulting in the stumble which is normal depending on temperature abberations.

 

My car did this for a few weeks everyday, then it just stopped doing it. Not sure if the ECU had mislearned something, and then eventually corrected itself?

 

In regards to the ECU the folks at RandD and myself have agreed the is a difference in the terms "learned" and "adapted" in ECU jargon......so indeed it appears your ECU "adapted" .